(a) Field of the Invention
This invention relates to a bimetal valve adapted to open or close a fluid flow conduit or to change the flow of a fluid from one path to another.
(B) Description of the Prior Art
When emission control devices are used in motor vehicles, the temperature conditions of the engines assume great importance to the efficient operation of the emission control devices. Accordingly, it becomes both desirable and necessary to provide signals associated with temperature changes in the internal combustion engines. These signals are transmitted in the form of a vacuum or atmospheric pressure through a bimetal valve.
However, prior art bimetal valves permit use of only one snapping or change-over temperature. As a result, where two or more change-over temperatures are required for three or more temperature ranges, such as a low temperature condition, a normal temperature condition after warm-up, and a super-heated condition of the internal combustion engine, two or more bimetal valves were required to be used in combination, to provide the desired pneumatic circuit. Representative prior art uses are disclosed in various publications.